U.S. patent application number 11/741107 was filed with the patent office on 2007-11-01 for dielectric ceramics and multi-layer ceramic capacitor.
Invention is credited to Shinichiro Ikemi, Kazumi Kaneda, Shusaku Ueda.
Application Number | 20070254799 11/741107 |
Document ID | / |
Family ID | 38649033 |
Filed Date | 2007-11-01 |
United States Patent
Application |
20070254799 |
Kind Code |
A1 |
Kaneda; Kazumi ; et
al. |
November 1, 2007 |
DIELECTRIC CERAMICS AND MULTI-LAYER CERAMIC CAPACITOR
Abstract
Dielectric ceramics include a sintered body comprising a
principal ingredient, when represented by: ABO.sub.3+aRe+bM+Zr
oxide where ABO.sub.3 is a barium titanate-based solid solution
having a perovskite structure, Re is at least one oxide of La, Ce,
Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and/or Y, M is at
least one oxide of Mg, Al, Cr, Mn, Fe, Ni, Cu, and/or Zn, a and b
each represents a mol number of the oxides per 1 mol of ABO.sub.3
within a range of: 1.100.ltoreq.Ba/Ti.ltoreq.1.700,
0.05.ltoreq.a.ltoreq.0.25, 0.05.ltoreq.b.ltoreq.0.25, Ti:Zr=95:5 to
60:40.
Inventors: |
Kaneda; Kazumi;
(Takasaki-shi, JP) ; Ueda; Shusaku; (Takasaki-shi,
JP) ; Ikemi; Shinichiro; (Takasaki-shi, JP) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Family ID: |
38649033 |
Appl. No.: |
11/741107 |
Filed: |
April 27, 2007 |
Current U.S.
Class: |
501/139 |
Current CPC
Class: |
C04B 2235/3418 20130101;
C04B 2235/3227 20130101; H01G 4/1227 20130101; C04B 2235/3279
20130101; H01B 3/12 20130101; C04B 2235/36 20130101; C04B 2235/3225
20130101; C04B 2235/3272 20130101; C04B 2235/6584 20130101; C04B
2235/3262 20130101; C04B 2235/3284 20130101; C04B 2235/3263
20130101; C04B 2235/6582 20130101; C04B 2235/79 20130101; C04B
2235/3224 20130101; C04B 2235/3281 20130101; C04B 35/49 20130101;
C04B 35/4682 20130101; C04B 2235/3241 20130101; C04B 2235/3201
20130101; C04B 2235/3217 20130101; C04B 2235/3248 20130101; C04B
2235/3215 20130101; C04B 2235/3229 20130101; H01G 4/30 20130101;
C04B 2235/365 20130101; C04B 2235/3206 20130101; C04B 2235/3244
20130101; C04B 35/62685 20130101 |
Class at
Publication: |
501/139 |
International
Class: |
C04B 35/468 20060101
C04B035/468 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 28, 2006 |
JP |
2006-150627 |
Claims
1. Dielectric ceramics of a sintered body comprising a principal
ingredient, when represented by: ABO.sub.3+aRe+bM+Zr oxide (where
ABO.sub.3 is a barium titanate-based solid solution represented by
a general formula showing a perovskite structure, Re is at least
one oxide of metal elements selected from La, Ce, Pr, Nd, Sm, Eu,
Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y, M is at least one oxide of
metal elements selected from Mg, Al, Cr, Mn, Fe, Ni, Cu, and Zn, a
and b each represent a mol number of each of oxides converted into
a chemical formula containing a metal element by one element based
on 1 mol of ABO.sub.3) within a range of:
1.100.ltoreq.Ba/Ti.ltoreq.1.700, 0.05.ltoreq.a.ltoreq.0.25,
0.05.ltoreq.b.ltoreq.0.25, the Zr oxide being within a range of:
Ti:Zr=95:5 to 60:40 when represented by a ratio of Zr to Ti, and a
glass component comprising SiO.sub.2 or mainly comprising
SiO.sub.2, in which the glass component comprising SiO.sub.2 or
mainly comprising SiO.sub.2 is within a range from 1.0 to 10.0
parts by weight based on 100 parts by weight of the barium
titanate-based solid solution.
2. Dielectric ceramics according to claim 1, wherein a portion of
Ba of the barium titanate-based solid solution is substituted by Sr
or Ca.
3. A multi-layer ceramic capacitor having plural dielectric ceramic
layers, an internal electrode formed between each of the dielectric
ceramic layers, and an external electrode connected electrically to
the internal electrode, in which the dielectric ceramic layer is a
sintered body comprising a principal ingredient, when represented
by: ABO.sub.3+aRe+bM+Zr oxide (where ABO.sub.3 is a barium
titanate-based solid solution represented by a general formula
showing a perovskite structure, Re is at least one oxide of metal
elements selected from La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er,
Tm, Yb, Lu and Y, M is at least one oxide of metal elements
selected from Mg, Al, Cr, Mn, Fe, Ni, Cu, and Zn, a and b each
represent a mol number of each of oxides converted into a chemical
formula containing a metal element by one element based on 1 mol of
ABO.sub.3) within a range of: 1.100.ltoreq.Ba/Ti.ltoreq.1.700,
0.05.ltoreq.a.ltoreq.0.25, 0.05.ltoreq.b.ltoreq.0.25, the Zr oxide
being within a range of: Ti:Zr=95:5 to 60:40 when represented by a
ratio of Zr to Ti, and a glass component comprising SiO.sub.2 or
mainly comprising SiO.sub.2, in which the glass component
comprising SiO.sub.2 or mainly comprising SiO.sub.2 is within a
range from 1.0 to 10.0 parts by weight based on 100 parts by weight
of the barium titanate-based solid solution and the internal
electrode is formed of Ni or Ni-based alloy.
4. Dielectric ceramics of a sintered body comprising: (i) a
principal ingredient represented by: ABO.sub.3+aRe+bM+Zr oxide
where ABO.sub.3 is a perovskite structure of a barium
titanate-based solid solution, Re is at least one oxide of metal
elements selected from La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er,
Tm, Yb, Lu and Y, a represents a sum total mol number of each Re
per 1 mol of ABO.sub.3, M is at least one oxide of metal elements
selected from Mg, Al, Cr, Mn, Fe, Ni, Cu, and Zn, b represents a
sum total mol number of each M per 1 mol of ABO.sub.3, wherein:
1.100.ltoreq.Ba/Ti.ltoreq.1.700, 0.05.ltoreq.a.ltoreq.0.25,
0.05.ltoreq.b.ltoreq.0.25, 95/5.ltoreq.Ti/Zr.ltoreq.60/40; and (ii)
a glass component comprising SiO.sub.2 accounting for 1.0 to 10.0
parts by weight per 100 parts by weight of the barium
titanate-based solid solution.
5. The dielectric ceramics accordingto claim 4, wherein the barium
titanate-based solid solution is constituted by BaTiO.sub.3.
6. The dielectric ceramics according to claim 4, wherein the barium
titanate-based solid solution is constituted by
(Ba.sub.1-x-yCa.sub.xSr.sub.y)TiO.sub.3 wherein x and y are
independently 0.02-0.20.
7. The dielectric ceramics according to claim 4, which has a
thickness of 1 .mu.m to 10 .mu.m.
8. The dielectric ceramics according to claim 4, which has a
permittivity of from 250 to 850 and satisfies X6S temperature
property.
9. A multi-layer ceramic capacitor comprising: plural dielectric
ceramic layers, each layer being constituted by the dielectric
ceramics of claim 4; an Ni internal electrode formed between each
of the dielectric ceramic layers; and an external electrode
connected electrically to the internal electrode.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention concerns dielectric ceramics mainly
comprising barium titanate (BaTiO.sub.3) and a multi-layer ceramic
capacitor using the same which can provide a multi-layer ceramic
capacitor having an internal electrode constituted with Ni or
Ni-based alloy.
[0003] 2. Description of Related Art
[0004] A demand for the size reduction and increase in the
capacitance has been increased more for multi-layer ceramic
capacitors for use in electronics such as portable equipments and
telecommunication equipments.
[0005] For manufacturing such reduced size and large capacitance
multi-layer ceramic capacitors, a dielectric ceramic composition
comprising a barium titanate-based solid solution and an additive
component, with less loss and heat generation under high frequency
and high voltage has been proposed as described, for example, in
JP-No. 3567759.
[0006] Further, JP No. 3361531 proposes a dielectric ceramic
composition mainly comprising barium titanate, capable of being
fired together with Ni in a reducing atmosphere and having a high
permittivity.
[0007] In recent years, further reduction in the size and increase
in the capacitance have been demanded for multi-layer ceramic
capacitors, and the thickness per one layer of ceramic layers after
firing has reached to a level of 10 .mu.m or less and, further, 5
.mu.m or less. While the dielectric ceramic composition shown in
JP-No. 3567759 has a high accelerated life time and a sufficient
reliability for a green sheet at the level of the thickness of 20
.mu.m as described in the examples of the publication, it involved
a problem that the reliability was lowered at a level of the
thickness of 10 .mu.m or less for one layer of the ceramic layers
after firing.
[0008] Further, low distortion capacitors with small distortion
have been demanded in recent years and the dielectric ceramic
composition shown in JP No. 3361531 has a high permittivity of 7000
or more and is suitable to increase in the capacitance but it is
not suitable for the use of the low distortion capacitor.
[0009] The present invention is intended to provide embodiments of
dielectric ceramics and an Ni internal electrode multi-layer
ceramic capacitor of higher reliability than usual, capable of
satisfying X6S for the temperature property of permittivity and
having a permittivity from 250 to 850.
SUMMARY OF THE INVENTION
[0010] According to an embodiment, the present invention provides
dielectric ceramics of a sintered body comprising a principal
ingredient, when represented by: ABO.sub.3+aRe+bM+Zr oxide (where
ABO.sub.3 is a barium titanate-based solid solution represented by
a general formula showing a perovskite structure, Re is at least
one oxide of metal elements selected from La, Ce, Pr, Nd, Sm, Eu,
Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y, M is at least one oxide of
metal elements selected from Mg, Al, Cr, Mn, Fe, Ni, Cu, and Zn, a
and b each represents a mol number of each of oxides converted into
a chemical formula containing a metal element by one element based
on 1 mol of ABO.sub.3) within a range of:
[0011] 1.100.ltoreq.Ba/Ti.ltoreq.1.700,
[0012] 0.05.ltoreq.a.ltoreq.0.25,
[0013] 0.05.ltoreq.b.ltoreq.0.25,
the Zr oxide being within a range of:
[0014] Ti:Zr=95:5 to 60:40
[0015] when represented by a ratio of Zr to Ti, and a glass
component comprising SiO.sub.2 or mainly comprising SiO.sub.2, in
which the glass component comprising SiO.sub.2 or mainly comprising
SiO.sub.2 is within a range from 1.0 to 10.0 parts by weight based
on 100 parts by weight of the barium titanate-based solid solution.
Further, a portion of Ba of the barium titanate-based solid
solution may be substituted by Sr or Ca.
[0016] The Ba/Ti ratio represents the ratio of Ba and Ti contained
in the barium titanate-based solid solution which does not always
agree with the A/B ratio in the perovskite structure. For example,
in view of BaTiO.sub.3 and (Ba.sub.1-x-yCa.sub.xSr.sub.y)TiO.sub.3,
while the A/B ratio is 1 for each of them, the Ba/Ti ratio is 1 for
BaTiO.sub.3 but it is 1-x-y for
(Ba.sub.1-x-yCa.sub.xSr.sub.y)TiO.sub.3.
[0017] Further, in another embodiment, the present invention
provides a multi-layered ceramic capacitor having plural dielectric
ceramic layers, an internal electrode formed between each of the
dielectric ceramic layers and an external electrode electrically
connected with the internal electrode, in which the dielectric
ceramic layer is formed of the dielectric ceramics described above,
and the internal electrode is formed of Ni or Ni-based alloy.
[0018] According to at least one embodiment, the invention can
provide dielectric ceramics constituting an Ni internal electrode
multilayer ceramic capacitor which can be fired at 1280.degree. C.
or lower, has a permittivity of from 250 to 850 and can satisfy X6S
temperature property.
[0019] Further, in an embodiment of the invention, since Ba/Ti is
specified, reliability such as life time property can be improved
over existent dielectric ceramics.
[0020] Further, in an embodiment, the invention is applicable to a
low distortion type multi-layer ceramic capacitor having a
permittivity of about 250 to 850.
PREFERRED EMBODIMENT OF THE INVENTION
[0021] Preferred embodiments according to dielectric ceramics of
the invention are to be described. In an embodiment, the dielectric
ceramics of the invention is a sintered body containing a barium
titanate-based solid solution, Re (Re is at least one oxide of
metal elements selected from La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy,
Ho, Er, Tm, Yb, Lu and Y), M (M is an oxide of metal element
selected from Mg, Al, Cr, Mn, Fe, Ni, Cu, and Zn) and a Zr oxide at
a composition ratio described above, to which a glass component
comprising SiO.sub.2 or mainly. comprising SiO.sub.2 is added as a
sintering aid. The glass component includes, for example,
Li.sub.2O--SiO.sub.2-based glass or B.sub.2O.sub.3--SiO.sub.2-based
glass.
[0022] Such dielectric ceramics are obtained as described below. At
first, BaCO.sub.3, TiO.sub.2, and ZrO.sub.2 are weighed and
prepared as the starting materials such that they are in a
composition ratio within the range of an embodiment of the
invention. In this case, CaCO.sub.3, or SrCO.sub.3 may be prepared
optionally. Further, instead of ZrO.sub.2, BaZrO.sub.3,
CaZrO.sub.3, or SrZrO.sub.3 may also be used. Water is added to the
starting materials and wet-mixed by using, for example, a ball
mill, bead mill, dispa mill, etc. The mixture is dried and calcined
at 1100.degree. C. to 1250.degree. C. to obtain a barium
titanate-based solid solution.
[0023] To the thus obtained barium titanate-based solid solution,
the Re ingredient (for example, Ho.sub.2O.sub.3), the M ingredient
(for example, MgO and MnO, MnCO.sub.3, Mn.sub.3O.sub.4) and the
sintering aid (for example SiO.sub.2) weighed so as to form a
composition ratio within the range of an embodiment of the
invention are added and wet-mixed by a ball mill or the like and
calcined at 700 to 900.degree. C. after drying, to obtain a
dielectric ceramic powder. The obtained dielectric ceramic powder
is used for forming a dielectric ceramic layer of a multi-layer
ceramic capacitor.
[0024] The present invention can equally be applied to a method of
manufacturing the dielectric ceramics.
[0025] For purposes of summarizing the invention and the advantages
achieved over the related art, certain objects and advantages of
the invention are described in this disclosure. Of course, it is to
be understood that not necessarily all such objects or advantages
may be achieved in accordance with any particular embodiment of the
invention. Thus, for example, those skilled in the art will
recognize that the invention may be embodied or carried out in a
manner that achieves or optimizes one advantage or group of
advantages as taught herein without necessarily achieving other
objects or advantages as may be taught or suggested herein.
[0026] Further aspects, features and advantages of this invention
will become apparent from the detailed description of the preferred
embodiments which follow.
DESCRIPTION OF THE ACCOMPANYING DRAWING
[0027] These and other features of this invention will now be
described with reference to the drawings of preferred embodiments
which are intended to illustrate and not to limit the invention.
The drawings are oversimplified for illustrative purposes and are
not to scale.
[0028] The FIGURE is a schematic view showing a cross-section of a
multi-layer ceramic capacitor.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0029] A multi-layer ceramic capacitor according to a preferred
embodiment of the invention is to be described with reference to
the figure. However, the preferred embodiment is not intended to
limit the present invention.
[0030] As shown in the figure, a multi-layer ceramic capacitor 1
according to this embodiment has a multi-layer ceramic body 2
comprising a plurality of dielectric ceramic layers 3 and internal
electrode 4 formed between the dielectric ceramic layers. An
external electrode 5 is formed on both end faces of the multi-layer
ceramic body 2 for electric connection with an internal electrode,
on which a first plating layer 6 and a second plating layer 7 are
formed optionally.
[0031] Then, a method of manufacturing the multi-layer ceramic
capacitor 1 is to be described. At first, a starting powder for
forming the dielectric ceramics of an embodiment of the invention
is provided. This is mixed with a butyral-based or acrylic-based
organic binder, a solvent, and other additives to form a ceramic
slurry. The ceramic slurry is sheeted by using a coating device
such as a roll coater to form a ceramic green sheet of a
predetermined thickness as the dielectric ceramic layer 3. An Ni or
Ni-based alloy conductive paste is coated in a predetermined
pattern shape on the ceramic green sheet by screen printing to form
a conductive layer as the internal electrode 4.
[0032] After laminating the ceramic green sheets formed with the
conductive layer by a required number, they are press bonded to
form a green multi-layer. After cutting and dividing the same into
individual chips, the binder is removed in an atmospheric air or a
non-oxidative gas such as nitrogen. After removal of the binder, a
conductive paste is coated on the exposure surface of the internal
electrode of the individual chip to form a conductive film as the
external electrode 5. The individual chip formed with the
conductive film is fired in nitrogen-hydrogen atmosphere (oxygen
partial pressure: about 10.sup.-10 atm) at a predetermined
temperature. For the external electrode 5, a conductive paste
containing a glass frit may be coated and baked to the internal
electrode exposure surface after firing the individual chip to form
the multi-layer ceramic 2. For the external electrode 5, metals
identical with those for the internal electrode can be used, as
well as Ag, Pd, AgPd, Cu, Cu-based alloy, etc. can be used.
Further, the first plating layer 6 is formed of Ni, Cu, etc. and
the second plating layer 7 is formed thereover with Sn or Sn-based
alloy above the external electrode 5, to obtain a multi-layer
ceramic capacitor 1.
[0033] In the present disclosure where conditions and/or structures
are not specified, the skilled artisan in the art can readily
provide such conditions and/or structures, in view of the present
disclosure, as a matter of routine experimentation. Also, in the
present disclosure, the numerical numbers applied in embodiments
can be modified by .+-.50% in other embodiments, and the ranges
applied in embodiments may include or exclude the endpoints.
EXAMPLE
Example 1
[0034] As the starting material, BaCO.sub.3, TiO.sub.2, ZrO.sub.2,
Gd.sub.2O.sub.3, MgO, and MnO were prepared so as to obtain
sintered bodies of the composition in Table 1. In Table 1, Ba, Ti,
and Zr are represented each as a ratio based on Ti+Zr being assumed
as 100. TABLE-US-00001 TABLE 1 Specimen Re:a M:b Aid No. Ba Ti Zr
Ba/Ti Kind Amount Kind 1 Amount Kind 1 Amount SiO.sub.2 101 * 102.0
94.0 6.0 1.085 Gd 0.12 Mg 0.10 Mn 0.01 2.0 102 100.1 91.0 9.0 1.100
Gd 0.12 Mg 0.10 Mn 0.01 2.0 103 102.0 60.0 40.0 1.700 Gd 0.12 Mg
0.10 Mn 0.01 2.0 104 * 105.0 60.0 40.0 1.750 Gd 0.12 Mg 0.10 Mn
0.01 2.0 105 * 107.0 97.0 3.0 1.103 Gd 0.12 Mg 0.10 Mn 0.01 2.0 106
105.0 95.0 5.0 1.105 Gd 0.12 Mg 0.10 Mn 0.01 2.0 107 * 95.0 58.0
42.0 1.638 Gd 0.12 Mg 0.10 Mn 0.01 2.0 * Out of the range of the
preferred embodiment of the invention.
[0035] The prepared BaCO.sub.3, TiO.sub.2, and ZrO.sub.2 were
wet-mixed by a ball mill and, after drying, calcined at
1100.degree. C. to obtain a barium titanate-based solid solution.
Then, Gd.sub.2O.sub.3, MgO, MnO, and Sio.sub.2 were added to the
barium titanate-based solid solution so as to form the compositions
in Table 1, wet-mixed by a ball mill and, after drying, calcined at
900.degree. C. to obtain dielectric ceramic powders. In Table 1,
the sintering aid is indicated by parts by weight based on 100
parts by weight of the barium titanate-based solid solution.
[0036] Polyvinyl butyral, organic solvent and plasticizer were
added and mixed to the powder to form a ceramic slurry. The ceramic
slurry was sheeted by a roll coater to obtain a ceramic green sheet
of 5 .mu.m thickness. An Ni-internal electrode paste was coated on
the ceramic green sheet by screen printing to form an internal
electrode pattern. The ceramic green sheets formed with the
internal electrode pattern were stacked by the number of 21 sheets,
press bonded and divisionally cut each into a size of 4.0.times.2.0
mm to form a green chips. The green chip was removed with the
binder in a nitrogen atmosphere, coated with an Ni external
electrode paste and fired in a reducing atmosphere
(nitrogen-hydrogen atmosphere, oxygen partial pressure: 10.sup.-10
atm) at a firing temperature shown in Table 2. For the thus
obtained multi-layer ceramic capacitor sized 3.2.times.1.6 mm with
a 3 .mu.m thickness for the dielectric ceramic layer, .di-elect
cons.r (permittivity), tan .delta., temperature property, and a
mean life time as the evaluation for the reliability were measured
and collected in Table 2. For the mean life time, test was
conducted for each 15 specimens at 150.degree. C. and under a load
of 25 V/.mu.m and evaluated as ".largecircle." in a case where the
time the insulation resistance was lowered to 1 M.OMEGA. or less
was 48 hrs or more. TABLE-US-00002 TABLE 2 Calcination Mean
Specimen temperature tan.delta. life No. .degree. C. .epsilon.r %
TCC time 101 * 1280 760 0.38 x x 102 1280 650 0.35 X6S
.smallcircle. 103 1280 430 0.30 X6S .smallcircle. 104 * 1280 -- --
-- -- 105 * 1280 -- -- -- -- 106 1280 510 0.31 X6S .smallcircle.
107 * 1280 400 0.28 X6S x
[0037] In view of the results described above, in a case where
Ba/Ti is from 1.100 to 1.700, Ti:Zr is from 95:5 to 60:40, ectric
ceramics and Ni internal electrode multi-layer ceramic capacitors
of high reliability, capable of satisfying the X6S property as a
permittivity temperature property and having a permittivity in a
range from 250 to 850 can be obtained. Specimens 104 and 105 were
not sintered favorably.
Example 2
[0038] Dielectric ceramic powders were formed in the same manner in
Example 1 so as to obtain sintered bodies of the compositions shown
in Table 3. In this case, the addition amount of Re was changed to
demonstrate the effect thereof. TABLE-US-00003 TABLE 3 Specimen
Re:a M:b Aid No. Ba Ti Zr Ba/Ti Kind Amount Kind Amount Kind 1
Amount Kind 1 Amount SiO.sub.2 201 104.0 80.0 20.0 1.300 La 0.09 Gd
0.03 Mg 0.11 Mn 0.01 2.0 202 104.0 80.0 20.0 1.300 Ce 0.09 Gd 0.03
Mg 0.11 Mn 0.01 2.0 203 104.0 80.0 20.0 1.300 Pr 0.09 Gd 0.03 Mg
0.11 Mn 0.01 2.0 204 104.0 80.0 20.0 1.300 Nd 0.09 Dy 0.03 Mg 0.11
Mn 0.01 2.0 205 104.0 80.0 20.0 1.300 Sm 0.09 Dy 0.03 Mg 0.11 Mn
0.01 2.0 206 104.0 80.0 20.0 1.300 Eu 0.09 Dy 0.03 Mg 0.11 Mn 0.01
2.0 207 104.0 80.0 20.0 1.300 Gd 0.12 -- -- Mg 0.11 Mn 0.01 2.0 208
103.0 80.0 20.0 1.288 Tb 0.09 Nd 0.03 Mg 0.11 Mn 0.01 2.0 209 103.0
80.0 20.0 1.288 Dy 0.12 -- -- Mg 0.11 Mn 0.01 2.0 210 103.0 80.0
20.0 1.288 Ho 0.12 -- -- Mg 0.11 Mn 0.01 2.0 211 102.0 80.0 20.0
1.275 Er 0.09 Gd 0.03 Mg 0.11 Mn 0.01 2.0 212 102.0 80.0 20.0 1.275
Tm 0.09 Gd 0.03 Mg 0.11 Mn 0.01 2.0 213 102.0 80.0 20.0 1.275 Yb
0.09 Gd 0.03 Mg 0.11 Mn 0.01 2.0 214 102.0 80.0 20.0 1.275 Lu 0.09
Gd 0.03 Mg 0.11 Mn 0.01 2.0 215 102.0 80.0 20.0 1.275 Y 0.09 Gd
0.03 Mg 0.11 Mn 0.01 2.0 216 * 104.0 80.0 20.0 1.300 Gd 0.02 -- --
Mg 0.11 Mn 0.01 2.0 217 104.0 80.0 20.0 1.300 Gd 0.05 -- -- Mg 0.05
Mn 0.01 2.0 218 104.0 80.0 20.0 1.300 Gd 0.25 -- -- Mg 0.15 Mn 0.01
2.0 219 * 104.0 80.0 20.0 1.300 Gd 0.30 -- -- Mg 0.11 Mn 0.01 2.0 *
Out of the range of the preferred embodiment of the invention
[0039] From the dielectric ceramic powder described above,
multi-layer ceramic capacitors were formed in the same manner as in
Example 1, and .di-elect cons.r, tan .delta., temperature property
and the mean life time were measured and collected in Table 4.
TABLE-US-00004 TABLE 4 Calcination Mean Specimen temperature
tan.delta. life No. .degree. C. .epsilon.r % TCC time 201 1280 300
0.32 X6S .smallcircle. 202 1280 310 0.30 X6S .smallcircle. 203 1280
315 0.25 X6S .smallcircle. 204 1280 330 0.20 X6S .smallcircle. 205
1280 335 0.22 X6S .smallcircle. 206 1280 360 0.21 X6S .smallcircle.
207 1280 380 0.21 X6S .smallcircle. 208 1280 400 0.22 X6S
.smallcircle. 209 1280 570 0.25 X6R .smallcircle. 210 1280 600 0.27
X6R .smallcircle. 211 1280 560 0.30 X6R .smallcircle. 212 1280 565
0.28 X6R .smallcircle. 213 1280 560 0.28 X6R .smallcircle. 214 1280
570 0.30 X6R .smallcircle. 215 1280 650 0.30 X6R .smallcircle. 216
* 1280 970 0.35 X6S x 217 1280 850 0.32 X6S .smallcircle. 218 1280
250 0.25 X6S .smallcircle. 219 * 1280 260 0.30 X6S x
[0040] From the results described above, in a case where the Re
composition ratio, that is, a is within a range:
0.05.ltoreq.a.ltoreq.0.25, it is possible to obtain dielectric
ceramics and Ni-internal electrode multi-layer ceramic capacitors
of high reliability, capable of satisfying the X6S property as the
permittivity temperature property and having a permittivity within
a range from 250 to 850.
Example 3
[0041] Dielectric ceramic powders were formed in the same manner as
in Example 1 so as to obtain sintered bodies of the compositions
shown in Table 5. In this case, the addition amount of M was
changed to demonstrate the effect thereof. TABLE-US-00005 TABLE 5
Specimen Re:a M:b Aid No. Ba Ti Zr Ba/Ti Kind Amount Kind Amount
Kind Amount SiO.sub.2 301 104.0 80.0 20.0 1.300 Gd 0.12 Al 0.07 Mn
0.02 2.0 302 104.0 80.0 20.0 1.300 Gd 0.12 Cr 0.07 Mn 0.02 2.0 303
104.0 80.0 20.0 1.300 Gd 0.12 Fe 0.07 Mn 0.02 2.0 304 104.0 80.0
20.0 1.300 Gd 0.12 Ni 0.08 Mn 0.01 2.0 305 104.0 80.0 20.0 1.300 Gd
0.12 Cu 0.08 Mn 0.01 2.0 306 104.0 80.0 20.0 1.300 Gd 0.12 Zn 0.08
Mn 0.01 2.0 307 * 104.0 80.0 20.0 1.300 Gd 0.12 Mg 0.02 Mn 0.01 2.0
308 104.0 80.0 20.0 1.300 Gd 0.12 Mg 0.04 Mn 0.01 2.0 309 104.0
80.0 20.0 1.300 Gd 0.12 Mg 0.24 Mn 0.01 2.0 310 * 104.0 80.0 20.0
1.300 Gd 0.12 Mg 0.29 Mn 0.01 2.0 * Out of the range of the
preferred embodiment of the invention
[0042] From the dielectric ceramic powders described above,
multi-layer ceramic capacitors were formed in the same manner as in
Example 1, and .di-elect cons.r, tan .delta., temperature property
and mean life time were measured and collected in Table 6.
TABLE-US-00006 TABLE 6 Calcination Mean Specimen temperature
tan.delta. life No. .degree. C. .epsilon.r % TCC time 301 1280 450
0.35 X6S .smallcircle. 302 1280 460 0.40 X6S .smallcircle. 303 1280
380 0.29 X6S .smallcircle. 304 1280 370 0.31 X6S .smallcircle. 305
1280 430 0.33 X6S .smallcircle. 306 1280 420 0.32 X6S .smallcircle.
307 * 1280 530 0.25 x -- 308 1280 450 0.20 X6S .smallcircle. 309
1280 290 0.22 X6S .smallcircle. 310 * 1280 260 0.24 X6S x
[0043] From the results described above, in a case where the M
composition ratio, that is, b is within a range: 0.05 <b 0.25,
it is possible to obtain dielectric ceramics and Ni-internal
electrode multi-layer ceramic capacitors of high reliability,
capable of satisfying the X6S property as the permittivity
temperature property and having a permittivity within a range from
250 to 850.
Example 4
[0044] Dielectric ceramic powders were formed in the same manner as
in Example 1 so as to obtain sintered bodies of the compositions
shown in Table 7. In this case, specimen 408 corresponds to the
example of JP-No. 3567759 and specimen 409 is a known composition.
As the glass component used as the sintering aid,
B.sub.2O.sub.3--SiO.sub.2--BaO glass was used in this case.
TABLE-US-00007 TABLE 7 Specimen A site Re:a M:b Aid No. Ba
substitution Ti Zr Ba/Ti Kind Amount Kind Amount Kind Amount
SiO.sub.2 Glass 401 * 104.0 -- -- 80.0 20.0 1.300 Gd 0.12 Mg 0.11
Mn 0.01 0.8 -- 402 104.0 -- -- 80.0 20.0 1.300 Gd 0.12 Mg 0.11 Mn
0.01 1.0 -- 403 104.0 -- -- 80.0 20.0 1.300 Gd 0.12 Mg 0.11 Mn 0.01
10.0 -- 404 * 104.0 -- -- 80.0 20.0 1.300 Gd 0.12 Mg 0.11 Mn 0.01
12.0 -- 405 104.0 -- -- 80.0 20.0 1.300 Gd 0.12 Mg 0.11 Mn 0.01 --
2.0 406 94.0 Ca 10.0 80.0 20.0 1.175 Gd 0.12 Mg 0.10 Mn 0.01 2.0 --
407 99.0 Sr 5.0 80.0 20.0 1.238 Gd 0.12 Mg 0.10 Mn 0.01 2.0 -- 408
* 100.0 -- -- 100.0 20.0 1.000 Gd 0.12 Mg 0.05 Mn 0.01 -- 2.0 409 *
101.0 -- -- 86.0 14.0 1.174 Ho 0.01 Mg 0.01 Mn 0.005 -- 0.5 * Out
of the range of the preferred embodiment of the invention
[0045] From the dielectric ceramic powders described above,
multiplayer ceramic capacitors were formed in the same manner as in
Example 1, and .di-elect cons.r, tan .delta., temperature property
and the mean life time were measured and collected in Table 8.
TABLE-US-00008 TABLE 8 Calcination Mean Specimen temperature
tan.delta. life No. .degree. C. .epsilon.r % TCC time 401 * 1280 --
-- -- -- 402 1280 550 0.25 X6S .smallcircle. 403 1260 270 0.35 X6S
.smallcircle. 404 * 1260 240 0.40 X6S x 405 1260 330 0.45 X6R
.smallcircle. 406 1280 340 0.25 X6S .smallcircle. 407 1280 320 0.24
X6S .smallcircle. 408 * 1280 400 0.20 X6R x 409 * 1280 6000 0.65 x
.smallcircle.
[0046] From the results described above, in a case where the
composition of the sintering aid is within a range from 1.0 to 10.0
parts by weight based on 100 parts by weight of barium
titanate-based solid solution, it is possible to obtain dielectric
ceramics and Ni-internal electrode multi-layer ceramic capacitors
of high reliability, capable of satisfying the X6S property as the
permittivity temperature property and having a permittivity within
a range from 250 to 850. Further, it can be seen that the
dielectric ceramics and the multi-layer ceramic capacitors of the
preferred embodiment of the invention have more excellent property
than usual.
[0047] From the results described above, the preferred embodiment
of the present invention can provide dielectric ceramics and
Ni-internal electrode multi-layer ceramic capacitors of higher
reliability than usual, capable of satisfying X6S property as the
permittivity temperature property and having a permittivity of 250
to 850. The present application claims priority to Japanese Patent
Application No. 2006-150627, filed Apr. 28, 2006, the disclosure of
which is incorporated herein by reference in its entirety.
[0048] It will be understood by those of skill in the art that
numerous and various modifications can be made without departing
from the spirit of the present invention. Therefore, it should be
clearly understood that the forms of the present invention are
illustrative only and are not intended to limit the scope of the
present invention.
* * * * *